The design of broadband microwave systems and modules for modern instrumentation applications presents a significant challenge. A typical microwave system will contain several active integrated circuit (IC) components as well as passive elements, both of which may be distributed in nature. Such a system is often too complex to permit complete simulation of the non-linear behavior at the transistor level of description. A complete system simulation can become practical, however, provided the design is done at a higher level of abstraction, using behavioral models of the nonlinear blocks or ICs. The behavioral models must describe the frequency dependent nonlinear behavior of the ICs and must describe properly the propagation of harmonic and intermodulation distortions through the system, to enable the designer to meet rigid specifications, while being simple enough to allow rapid simulation.
It is desirable, therefore, to generate an extended nonlinear frequency domain behavioral model from automated large-signal vector network measurements and from automated simulations and analysis of detailed circuit-level models. Such a ‘black-box’ behavioral model should require no a priori knowledge of the device physics or circuit configuration of the nonlinear component.